Liquid fuel stove control means



Feb. 25, 1941. c. A. HOFF 2,232,947

LIQUID FUEL STOVE CONTROL MEANS Filed June 2, 1938 2 Sheets-Sheet 1 INVENTOR CHESTER A. HOPE I ATTORN EY-5 9 c. A. HOFF LIQUID FUEL} STOVE CONTROL MEANS Filed June 2, 1938 2 Sheets-Sheet 2 INVENTOR C HESTER A. HOFF f fMJ L ATTORNEYS Patented Feb. 25, 194-1 lJNilED stares 7 2,232,947 I LIQUID FUEL srovs CONTROL MEANS Chester A. Hoff, Akron, Ohio,

assignor to The Akron Lamp & Manufacturing Company, Akron, Ohio, a. corporation of Ohio Application June 2,1938, Serial No. 211,363 10 Claims. (01. 1534s) This invention relates to improved control means for stoves or heaters employing liquid fuel, such as gasoline or other volatile liquids.

In stoves of this character the liquid fuel is usually delivered under pressure from a supply tank to a heated gas generating means for conversion into fuel gas. This generating means must heat the fuel to a temperature which will convert it into a gas so that little or no liquid fuel will pass beyond the generator. It has,

therefore, been customary to initially preheat the generator to the desired temperature before the liquid fuel is passed therethrough and this preheating is accomplished by delivering a vapor from the fuel tank, comprised of a mixture of air and gas; to'a burner located beneath the generator, whereby this vapor is ignited to heat the generator. When the generator has been heated to the desired temperature the vapor is cut off and liquid fuel passed into the generator, part of the gas generated being burned beneath the generator to maintain the latter at the desired temperature.

Originally it was customary to operate manually the valve which controls the passage of vapor to preheat the generator as well as the valve which controls the passage of liquid fuel, and there have been several attempts made to control automatically the operation of the liquid fuel valve. It will be obvious, however,

that the most desirable structure, and it is an object of this invention to provide such a structure, is one in which the liquid fuel valve is operated automatically when the generator becomes heated to the desired temperature and in which the vapor valve is automatically closed as soon as or very shortly after the liquid fuel valve is opened.

Another object of the invention is to accomplish the automatic operation of the valves by thermal expansion and contraction of the generator tube.

A further object is to provide novel means for initially opening the vapor valve and for closing said valve when the liquid fuel valve is opened. A further object is to provide a generator tube and securing means therefor which does not require constant adjustment, and which may be quickly and accurately assembled in proper position to insure operation of thevalves under thermal movement of the-generator tube.

Other objects and advantages will become apparent from the following description taken in conjunction with the accompanying drawings...

In the drawings:

Figure. l is a plan view of control means in properposition in a stove, with only part of the latter being shown;

Figure 2 is an enlarged section of the operating valves and mechanisms associated therewith,

taken substantially on line 22 of Fig. 3; Figure 3 is a similar section taken substantially on line 3-3 of Fig. 1; and

Figure 4 is asimilar section taken substantially on line i l of Fig. 1. 19

Referring to the drawings the numeral I!) designates the frame of a stove which supports a plurality :of burners H controlled by operating handles 12 in the customary manner. A handle it controls the operation of a burner located in the oven compartment (not shown). The burners are fed from a mixing chamber I4 and a manifold I5 in the usual way. i

The generator comprises a tube l6 having therein a longitudinal passageway I! (Fig. fl) through which the fuel is fed to the mixing chamber Hi. This tube is formed of a suitable metal which will expand under the action of heat and which will retract as it cools off. A stem l8 extends through tube It and has a needle point 25 I9 thereon which controls the flow of fuel through a port 20 into the mixing chamber in the customary manner. Stem l8 has a portion 2| threaded into engagement with an extension 22 welded or otherwise suitably secured to the end of tube It whereby the needle point I!) may be controlled by turning the knob 23 on the outer end of the stem. The extension 22 is to be considered as a part of the generator and will be later referred to. The threaded portion 2| of the 5 stem is provided with a plurality-of longitudinal grooves 24 communicating with passageway H, which grooves comprise passageways for the fuel to pass this portion of the stem, as will be understood. r

The outer end of tube I6 is threaded into one end of an enlarged tubular casting I6 which surrounds stem l8 and which carries a suitable packing gland in its outer end to prevent leakage around the stem. The casting I 5. is provided 45 with a port 25 towhich is coupled one end of a U-shaped feed line 26, the opposite end of which is coupled to a valve housing 2'! having an outlet port 28 communicating with feed line 26. The housing 27 may be suitably supported by the stove structure and it is also provided with an inlet port 29 which communicates with one end of a feed line 3|] adapted to deliver liquid fuel under pressure to the valve housing from a supply tank (not shown). Ports 2B and 28 communicate at their inner ends with a chamber 3| in which a conically-headed valve stem 32 is located, the head of said stem being arranged to open and close inlet port 29. Stem 32 is provided with a shoulder 33 against which bears one end of a coil spring 34 that surrounds stem 32 and has its other end bearing against a wall of chamber 3|. The arrangement is such that spring 34 has a normal bias tounseat stem 32 and open port 29.

A valve cap 35 is threaded into housing 21 'as at 36 and has a central opening 31 which slidably receives a plunger 38 having an enlarged head 39 on its inner end whereby the head will not P ss through opening 31. Between head 39 and housing 21, one or more thin metallic sealing discs 40 are arranged. The valve members are assembled as shown in Fig. 2 with head 39 of the plunger arranged inwardly of opening 31 and bearing against discs 49. The latter bear against stem 32 and are flexible enough to permit movement of the stem and plunger 38 in response to the action of spring 34. Thus, in order to seat valve stem 32, plunger 38 is moved inwardly to its full extent and is held in this position to keep port 29 closed. As soon as plunger 38 is released, spring 34 will move the valve stem to open port 29 and at the same time the plunger will be moved outwardly until head 39 bears against the inner wall of cap 35.

A port 4 communicates at one end with valve chamber 3| and serves as an inlet port for the latter, while the opposite end of port 4| communicates with a valve chamber 42 in respect to which it serves as an outlet port. Chamber 42 is also formed in housing 21 and an inlet port 43 leads to this chamber. The latter port is adapted to be opened and closed by the conical portion 44 of a valve stem 45 arranged in an opening 46 formed centrally of a valve cap 41 which is threaded into the housing as at 48. Interposed between the housing and cap 41 are one or more metallic sealing discs 49 having a central opening 50 which permits movement of stem 45 through the discs. Opening 46 is in communication with one end of a feed line 5| which leads to the fuel tank (not shown) and which is adapted to carry vapor from the top of the tank above the liquid to the valve housing. Arranged in opening 46 and surrounding stem 45 is a coil spring 52 which engages the cap wall at one end and the head 44 of -stem 45 at the other end. Spring 52 has a normal bias to seat stem 45 whereby port 43 will be closed.

Opposite cap 41, another cap 53, having a central aperture 54 is arranged, being threaded into housing 21 as at 55. Aperture 54 slidably receives a plunger 55 provided with a head 51 enlarged so that it cannot pass through aperture 54. One or more metallic sealing discs 58, similar to discs 4|], are arranged between housing 21 and cap 53, and the head of stem 45 has a reduced extension 59 provided with an enlarged end 6|! which bears against discs 58. As will be noted from Fig. 2, when plunger 56 is moved inwardly,

'discs 58 will flex sufficiently to permit movement of valve stem 45 against the action of spring 52 to open port 43. When plunger 56 is released, spring 52 will seat stem 45 and close port 43, at the same time moving the plunger outwardly until head 51 engages the inner wall of cap 53.

Referring to Fig. 4, the inner end of the generator tube is provided with an annular groove 6| which is tapered at one end as at 62, and a set screw or regulating screw 63 is threaded through the front wall of mixing chamber l4 into engagement with the grooved portion of the generator. The inner end of screw 63 is adapted to engage the tapered end of the groove 6| to tightly hold this end of the generator in proper position. Slightly rounded edges 64 are formed on the screw end, and it makes no difierence what point on the tapered portion of the tube is initially engaged by the end of the screw, since continued tightening of the screw will cause it to assume the position shown in Fig. 4. In assembling the inner end of the tube with the mixing chamber, screw 63 is first raised to permit the tube end to pass through the opening in the wall of the latter chamber. As soon as groove 6| becomes alined with the end of the screw, the latter is partially moved down into the groove enough to prevent withdrawal of the tube end. The tube is then pulled longitudinally until the tapered portion 62 engages the end of the screw. Then the screw is completely tightened whereby the parts will assume the position shown in Fig. 4. Thus, it will be readily seen that the inner end of the tube may be quickly and accurately assembled in proper relation with the mixing chamber. Should the assembly become loose, or should it become necessary to remove the tube, the correct position can again be found immediately by following the foregoing instructions.

The casting l6 which receives the front end of tube I6 is supported for limited longitudinal sliding movement, in response to the expansion and contraction of the tube H5, in a bracket 65 secured to valve housing 21 by means of a nut 56. The upper portion of this bracket is cut away centrally to provide an opening 61 in which the casting rests, as shown in Fig. 3. Formed on the upper surface of the casting is a rectangular shaped lug 68 which snugly fits between the walls of opening 61 without obstructing the limited longitudinal movement of the casting. This lug 68 prevents turning of the casting after it has been placed in proper position in bracket 65.

Depending from casting l6 adjacent its outer end is another lug 69 arranged whereby its lower end is outwardly of a bar 10 pivoted as at 1| to the end of an arm 12 secured to housing 21 as by means of a nut 13. A regulating screw 14 is threaded through the lower end of lug 69 into engagement with bar 10. When the stove is not in use, bar 10 forms an angle of approximately with arm 12, and plunger 38 is so arranged that bar 10 will hold it inwardly against the action of spring 34 to keep port 29 closed. With screw 14 tightly in engagement with bar 10 the relationship of the parts as just described, and as shown in Fig. 2, will be maintained. When, however, the tube |6 expands under the application of heat, casting l6, lug 69 and screw 14 will move sufficiently to permit spring 34 to open port 29 and move plunger 38 outwardly, also moving bar 10 slightly about its pivot point.

Adjacent its free end, bar 10 receives the threaded end of a sleeve 15 which extends through an opening in the front wall of the stove as shown in Fig. 1. Mounted for limited turning movement in sleeve 15 is a rod 16 the ends of which extend beyond the ends of the sleeve. On the outer end of rod 16 an operating handle 11 is suitably arranged while on its inner end a cam 18 is secured as by means of a pin 19. Cam 18 is of suitable thickness whereby when rod 16 is turned through the medium of handle 11, the cam will engage the inner face of bar 10 and force plunger 56 inwardly against the action of spring 52, unseating valve stem 45 and opening port 43. The shape of cam I8 is shown in Fig. 3 and it is eccentrically secured to rod 16 adjacent one corner of the cam and is provided with a Weighted portion 19. The broken lines in Fig. 3 show the cam in its inoperative position, from which it is moved counterclockwise to operative position between bar 10 and plunger 56. A pin 80 extends outwardly from the cam in a position to engage the lower surface of bar 10 and prevents movement of the cam past its operative position.

Cam 18 can be quickly turned to its operative position to open port 43 and it will remain in this position until bar 10 moves about its pivot point as a result of the expansion of tube I6. Since cam 18 is movable with bar 10 it will move outwardly and permit spring 52 to close port 43 and move plunger 56 outwardly until the head 51 of the latter engages the wall of cap 53. Continued outward movement of bar HI and cam 18 will move the latter away from the plunger 56 and the weighted lower end of the cam will pull the latter downwardly to the broken line position of Fig. 3. As the cam drops to the latter position,

rod 16 will be turned back to its initial position and the weight of handle 11 on the front end of the rod will assist the cam in turning the rod. As shown in Fig. 3, one of the operating rods 8| for one of the burners I I is arranged in the path of cam 18 to prevent its return past the broken line position illustrated.

In operation, the parts are assembled to secure the front end of the generator properly in the mixing chamber I4 and to permit longitudinal expansion of tube "5 so as to move casting l6. Regulating screw 14 is adjusted to close port 29 in the manner indicated and cam 18 is in inoperative position so that port 43 is also closed. This is the normal condition of the parts when the stove is not in use. To use the stove the port 20 leading to the mixing chamber is opened by turning handle 23. Cam 18 is turned to operative position by turning handle 11 thus opening port 43. Vapor, comprising a mixture of gas and air from the fuel tank above the liquid fuel, will pass through valve chamber 42, port 4| chamber 3|, port 28 and feed line 26, into casting Hi, from which it will flow through passageway l'l into mixing chamber M. The vapor will next pass through the manifold to the various burners including a plurality of small burners 82 arranged beneath tube IS in position to apply heat to the latter over a substantial portion of its length. The vapor from burners 82 is now ignited and tube l6 heated to a temperature sufficient to generate gas from the liquid fuel to be subsequently admitted to the generator.

Since the temperature necessary to generate gas is ordinarily high enough to cause longitudinal expansion of tube Hi, the latter will expand sufliciently to move lug B9 and adjusting screw 14 whereby bar will turn on its pivot and permit the opening of port 29. When port 29 opens, liquid fuel will flow from the fuel tank through valve chamber 3| in the generator where gas is formed which passes into the mixing chamber and then into the various burners. Some of this gas will pass into burners 82 and burn beneath the generator to keep the latter at the desired temperature to generate gas from the liquid fuel.

Port 43 remains open for a very short time after port 29 is opened so that gas generated from the liquid fuel will reach burners 82 before the fiow of vapor is cut off, thus insuring a continuous flame under the generator. Very little time is required for the generated gas to. reach burners 82 and port 43 will close as soon as cam 18 moves outwardly with bar 10 far enough to permit spring 52 to seat valve 45. The cam will drop to inoperative position as previously explained and port 43 will remain closed, shutting off the flow of vapor to the generator, until the cam is manually operated again to open it.

With port 29 open, liquid fuel will be continuously fed to the generator, but should the burners 82 not function for any reason, or should the flame go out, tube l6 will quickly cool and contract, returning bar 10 to the position shown in Fig. 2 and closing port 29 completely shutting off the stove. This safety feature is entirely automatic.

It is believed to be apparent that I have provided novel structure in which the liquid fuel valve opens automatically when the generator becomes heated to the desired temperature and in which the vapor valve is automatically closed very shortly after the liquid fuel valve is opened. Also, the liquid fuel valve will close automatically should anything prevent proper heating of the generator tube. Furthermore, I have provided a novel type of securing means for the inner end of the generator whereby constant adjustment is not required and whereby the parts may be quickly and accurately assembled in proper position to insure operation of the valves under thermal movement of the generator tube.

Although I have shown and described the preferred form of my invention it will be obvious that various changes may be made therein without departing from the spirit of the invention or from the scope of the subjoined claims.

What is claimed is:

1. In combination with a liquid fuel stove including a generator tube formed of material expansible under the application of heat, a valve controlling the passage of vapor into said generator, a second valve controlling the passage of liquid into said generator, means including a cam for opening said first valve, and means automatically operable after said generator has been heated to a temperature sufficient to expand same first to open said second valve and then to release said cam to close said first valve, said cam being manually operable to open said first valve and being operable by gravity to close said first valve.

2. In combination with a liquid fuel stove including a generator tube formed of material expansible under the application of heat, a valve controlling the passage of fuel in one state into said generator, a spring having a normal bias to close said valve, a plunger operable to open said valve against the action of said spring, a second valve controlling the passage of fuel in a different state into said generator, a second spring having a normal bias to open said second valve, a second plunger operable to close said second valve against the action of said second spring, means for operating said first plunger to open said first valve, and mechanism for operating said second plunger to close said second valve, said mechanism being automatically operable after said generator has been heated to a temperature sufiicient to expand same to release both of said plungers to open said second valve and to close said first valve, said k mechanism being operable subsequently to close said second valve automatically upon contraction of the generator tube without opening said first valve.

3. A combination as recited in claim 2 wherein said means comprises a cam manually operable to move said first plunger to open said first valve and operable by gravity to release said first plunger to close said first valve.

4. A combination as recited in claim 2 wherein said generator tube is formed of a metal expansible under the application of heat, and wherein said mechanism comprises a pivoted bar manually operable to move said second plunger to close said second valve and operable upon expansion of said generator tube to release said second plunger to open said second valve.

5. A combination as recited in claim 2 wherein said generator tube is formed of a metal expansible under the application of heat, and wherein said mechanism comprises a pivoted bar manually operable to move said second plunger to close said second valve and operable upon expansion of said generator tube to release said second plunger to open said second valve, and wherein said means comprises a cam manually operable to move said first plunger to open said first valve and operable by gravity to release said first plunger to close said first valve.

6. A combination as recited in claim 2 wherein said mechanism comprises a pivoted bar engageable with said second plunger to close said second valve, and wherein said means comprises a cam frictionally held between said bar and said first plunger to open said first valve.

'7. Control means for a liquid fuel stove comprising a metal generator tube expansible under the application of heat, a valve controlling the passage of fuel in one state into said generator,

a second valve controlling the passage of fuel in a different state into said generator, and means automatically operable after expansion of said generator tube first to open said second valve and then to close said first valve, said means being operable subsequently to close said second valve automatically upon contraction of said generator tube without opening said first valve.

8. A combination as recited in claim I wherein said means includes a pivoted bar operable to control said second valve and a cam carried on said bar and operable to control said first valve.

9. A combination as recited in claim 7 wherein said valves each have a spring actuated plunger associated therewith, said means including a pivoted bar operable to engage the plunger of said second valve and a cam carried on said bar and operable to engage the plunger of said first valve.

10. Control means for a liquid fuel stove comprising a metal generator tube expansible under the application of heat, a valve controlling the passage of fuel in one state into said generator, a second valve controlling the passage of fuel in a different state into said generator, means including a cam for manually opening said first valve, and means including a pivoted bar operable automatically upon expansion of said generator tube first to open said second valve and then to release said cam to close said first valve, said last named means being operable subsequently to close said second valve automatically upon contraction of said generator tube without opening said first valve.

CHESTER A. HOFF. 

